The invention relates to a process for casting metals, in particular alloys with low melting points, during which process liquid metal is filled from the bottom to the top into a casting mold by way of a casting runner and a filling hole arranged at the lowest point of the casting mold, and to an apparatus to effect such a process.
Such processes are employed, for example, during the production of lost cores for injection molded plastic parts. During such process top casting must be avoided, so that the casting takes place by necessity at the lowest point of the mold. To date the liquid metal during the process of the aforementioned kind has been filled under pressure into the casting mold and the casting pressure has been maintained until the metal has totally solidified in the casting mold. After the metal has solidified, the resulting sprue or runner has to be removed and the filling point has to be ground smooth.
The cores produced in this manner are used, among other things, for mass producing plastic parts in the automobile industry, where it is important on account of high quantity requirements to hold the cost of production as low as possible. However, these costs are significantly increased by the requisite subsequent treatment and the additionally required machines or manual activity.